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OpenCL In Action: Post-Processing Apps, Accelerated

Test Setup And Benchmarks

In planning this series, we asked ourselves what readers really need to know about exploiting DirectCompute/OpenCL acceleration. Is it difficult? No. The drivers enable functionality by default, and most applications able to leverage the improvements have what amounts to an on/off switch to either use the feature or not. We’re stumped as to why anyone would disable acceleration, but it does make our job of testing the features much easier.

Right out of the gate, we're testing two OpenCL-enabled post-processing applications: ArcSoft’s Total Media Theater (TMT) 5.2 (in pre-release at our time of testing) and MotionDSP’s vReveal.

The SimHD component of TMT now uses OpenCL and GPU-based processing to interpolate standard-definition video (480p) to near-HD levels (720p) in real-time. To test this, we played a DVD copy of Minority Report with (GPU) and without (CPU) OpenCL enabled. We ran in comparison split-screen mode with SD on the left half of the image and near-HD on the right half. ArcSoft provides four main features within SimHD—upscaling, dynamic lighting, denoise, and smoothness—but we only tested with the first three enabled and set to maximum. The smoothness option was not available when testing in a CPU-only processing scenario, so we omitted it to have consistency across our test parameters. Also, we only tested SimHD with AMD's Radeon HD 5870 because, as of our testing, Total Media Theater wouldn't cooperate with AMD's Radeon HD 7970. That's not surprising, considering we also had trouble getting GPU-accelerated compute working in CyberLink's Media Espresso in our AMD Radeon HD 7950 Review: Up Against GeForce GTX 580 coverage.

MotionDSP’s vReveal gained fame as one of the first and best consumer-oriented applications for fixing shaky video. The amount of processing required to pull this effect off in real-time is formidable, since several frames of video must be analyzed at once and, many features tracked and recompiled across those frames. At 1080p, this load can cripple some systems. Today, vReveal 3 also includes several additional features, including sharpening, brightening, and noise cleaning, all of which can run concurrently with stabilization. Ideally, you'd have all of this rendering in real-time.

In our tests, we used two sample video clips that ship with the downloadable binary of vReveal 3: the “Barcelona” file at 480p and the “San Francisco” file at 1080p. We tested these twice, once with only basic stabilization enabled and then in a more demanding configuration with five effects piled on. We then tested these in CPU-only, APU-accelerated, and two different discrete GPU-based configurations.

Test Hardware
Test System 1
ProcessorAMD FX-8150 (Zambezi) 3.6 GHz, Socket AM3+, 8 MB Shared L3 Cache, Turbo Core enabled, 125 W
MotherboardAsus Crosshair V Formula (Socket AM3+), AMD 990FX/SB950
Memory8 GB (2 x 4 GB) AMD Performance Memory AE34G1609U2 (1600 MT/s, 8-9-8-24)
SSD240 GB Patriot Wildfire SATA 6Gb/s
GraphicsAMD Radeon HD 7970 3 GB
AMD Radeon HD 5870 1 GB
Power SupplyPC Power & Cooling Turbo-Cool 860 W
Operating SystemWindows 7 Professional, 64-bit
Test System 2
ProcessorAMD A8-3850 (Llano) 2.9 GHz, Socket FM1, 4 MB L2 Cache, 100 W, Radeon HD 6550D Graphics
MotherboardGigabyte A75-UD4H (Socket FM1), AMD A75 FCH
Memory8 GB (2 x 4 GB) AMD Performance Memory AE34G1609U2 (1600 MT/s, 8-9-8-24)
SSD240 GB Patriot Wildfire SATA 6Gb/s
GraphicsAMD Radeon HD 7970 3 GB
AMD Radeon HD 5870 1 GB
Power SupplyPC Power & Cooling Turbo-Cool 860 W
Operating SystemWindows 7 Professional, 64-bit
Test System 3
PlatformGateway NV55S05u
ProcessorAMD A8-3500M (Llano), 1.5 GHz, Socket FS1, 4 MB L2 Cache, 35 W, Radeon HD 6620G Graphics
Memory4 GB Elpida PC3-10600S-9-10-F22 GB Hynix PC3-10600S-9-10-B1
Hard DriveWestern Digital Scorpio Blue 640 GB, 5400 RPM, 8 MB Cache, SATA 3Gb/s
Operating SystemWindows 7 Home Premium, 64-bit
Test System 4
PlatformHP Pavillion dv6
ProcessorIntel Core i5-2410M (Sandy Bridge), 2.3 GHz, Socket G2, 3 MB Shared L3 Cache, 35 W, HD Graphics 3000
Memory4 GB Samsung PC3-10600S-09-10-ZZZ
Hard DriveSeagate Momentus 7200.4 500 GB, 7200 RPM, 16 MB Cache, SATA 3Gb/s
Operating SystemWindows 7 Professional, 64-bit
  • DjEaZy
    ... OpenCL FTW!!!
    Reply
  • amuffin
    Will there be an open cl vs cuda article comeing out anytime soon? :ange:
    Reply
  • Hmmm...how do I win a 7970 for OpenCl tasks?
    Reply
  • deanjo
    DjEaZy... OpenCL FTW!!!
    Your welcome.

    --Apple
    Reply
  • bit_user
    amuffinWill there be an open cl vs cuda article comeing out anytime soon?At the core, they are very similar. I'm sure that Nvidia's toolchain for CUDA and OpenCL share a common backend, at least. Any differences between versions of an app coded for CUDA vs OpenCL will have a lot more to do with the amount of effort spent by its developers optimizing it.
    Reply
  • bit_user
    Fun fact: President of Khronos (the industry consortium behind OpenCL, OpenGL, etc.) & chair of its OpenCL working group is a Nvidia VP.

    Here's a document paralleling the similarities between CUDA and OpenCL (it's an OpenCL Jump Start Guide for existing CUDA developers):

    NVIDIA OpenCL JumpStart Guide

    I think they tried to make sure that OpenCL would fit their existing technologies, in order to give them an edge on delivering better support, sooner.
    Reply
  • deanjo
    bit_userI think they tried to make sure that OpenCL would fit their existing technologies, in order to give them an edge on delivering better support, sooner.
    Well nvidia did work very closely with Apple during the development of openCL.
    Reply
  • nevertell
    At last, an article to point to for people who love shoving a gtx 580 in the same box with a celeron.
    Reply
  • JPForums
    In regards to testing the APU w/o discrete GPU you wrote:

    However, the performance chart tells the second half of the story. Pushing CPU usage down is great at 480p, where host processing and graphics working together manage real-time rendering of six effects. But at 1080p, the two subsystems are collaboratively stuck at 29% of real-time. That's less than half of what the Radeon HD 5870 was able to do matched up to AMD's APU. For serious compute workloads, the sheer complexity of a discrete GPU is undeniably superior.

    While the discrete GPU is superior, the architecture isn't all that different. I suspect, the larger issue in regards to performance was stated in the interview earlier:

    TH: Specifically, what aspects of your software wouldn’t be possible without GPU-based acceleration?

    NB: ...you are also solving a bandwidth bottleneck problem. ... It’s a very memory- or bandwidth-intensive problem to even a larger degree than it is a compute-bound problem. ... It’s almost an order of magnitude difference between the memory bandwidth on these two devices.

    APUs may be bottlenecked simply because they have to share CPU level memory bandwidth.

    While the APU memory bandwidth will never approach a discrete card, I am curious to see whether overclocking memory to an APU will make a noticeable difference in performance. Intuition says that it will never approach a discrete card and given the low end compute performance, it may not make a difference at all. However, it would help to characterize the APUs performance balance a little better. I.E. Does it make sense to push more GPU muscle on an APU, or is the GPU portion constrained by the memory bandwidth?

    In any case, this is a great article. I look forward to the rest of the series.
    Reply
  • What about power consumption? It's fine if we can lower CPU load, but not that much if the total power consumption increase.
    Reply